using System;
using System.IO;

namespace Org.BouncyCastle.Bcpg
{
	/// <remarks>Basic packet for a modification detection code packet.</remarks>
	public class ModDetectionCodePacket
		: ContainedPacket
	{
		private readonly byte[] digest;

		internal ModDetectionCodePacket(
			BcpgInputStream bcpgIn)
		{
			if (bcpgIn == null)
				throw new ArgumentNullException("bcpgIn");

			this.digest = new byte[20];
			bcpgIn.ReadFully(this.digest);
		}

		public ModDetectionCodePacket(
			byte[] digest)
		{
			if (digest == null)
				throw new ArgumentNullException("digest");

			this.digest = (byte[]) digest.Clone();
		}

		public byte[] GetDigest()
		{
			return (byte[]) digest.Clone();
		}

		public override void Encode(
			BcpgOutputStream bcpgOut)
		{
			bcpgOut.WritePacket(PacketTag.ModificationDetectionCode, digest, false);
		}
	}
}
